RELATION BETWEEN ISOMETRIC TENSION, POSTMORTEM pH DECLINE AND TENDERNESS OF POULTRY BREAST MEAT

Postmortem changes in isometric tension, pH and shear force of poultry breast meat were studied to determine the relation between rigor contraction and tenderness. Strips of pectoralis major muscle immersed in isotonic saline solution held at 25°C developed measurable tension when their pH dropped to 6.1–6.3. The tension gradually increased until the pH dropped to a final value of 5.5–5.8, then started to decline. Muscle cooked at the start of tension development had the highest shear force. After that the shear force of the cooked meat gradually declined to a minimum value. The results indicate a high correlation (r=0.97) between ultimate shear force and degree of maximum tension developed during rigor.